laser-lovers@uw-beaver (12/13/84)
From: ihnp4!utzoo!henry@uw-beaver.arpa
One wart of the HP LaserJet, and probably all printers based on the
Canon LBP-CX, is that the output catcher tray won't hold very many
sheets before it starts to jam up. The obvious thing to do is to take
the silly plastic tray off, and arrange your own catcher.
Unfortunately, the simple approach of just letting the sheets fall to
the table beside the printer doesn't work well. The leading edge of
sheets coming out tends to catch on sheets already there, with the
result that some of the emerging sheets curl over and end up face-down.
Elevating the catcher surface above the table fixes this, but then
friction with the catcher tends to make the trailing edges of emerging
sheets hang on the lip of the printer rather than flopping down. The
end result of this, fairly quickly, is that the edge of an emerging
sheet goes *under* a hung-up sheet and they end up in the wrong order.
After some experimenting, we've come up with a solution that works
pretty well. What's needed is a ramp, sloping down and away from the
printer. The "touchdown point" for the leading edge needs to be close
enough and high enough that it won't curl over, while the ramp as a
whole needs to be steep enough that emerging sheets will slide to the
bottom rather than sitting there with their trailing edges on the
printer lip. We've been unable to accomplish this without going below
the level of the table. But by putting the printer near the edge and
running the ramp over the edge, we've made it work.
Our ramp is 11 inches long, measured along the slope; the surface is
actually the light cardboard packing sheet from a box of line-printer
paper. The upper edge of the ramp is 2+1/4 inches above the table, and
just touching the edge of the paper cassette. The lower edge is 2+3/4
inches below the edge of the table, about 5+1/4 inches out from it.
At the lower edge there is a vertical end stop sticking up to stop the
paper sliding off. The surface of the ramp is quite smooth. We've cut
a notch in the upper edge of the ramp, beside the printer, to make it
easier to get a finger under a stack of sheets. Since the paper touches
down on the ramp a couple of inches down from the top edge, a notch at
the top doesn't cause any problems.
This ramp has worked perfectly since we figured it out, including times
when quite large amounts of output have accumulated on it. Its one real
disadvantage is that we have to flip it up when we need to change paper.
It also wouldn't work well, at all, with a legal-sized paper cassette.
Apart from that, I quite recommend it.
I should add that the curling and touchdown properties of paper are
sensitive to the type of paper. We're using Xerox paper. Some thinner
letterhead papers curl so badly that this ramp design probably wouldn't
work at all for them.
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henry